The “O” Antiphons are sung before the Gospel reading each weekday from December 17th through the 23rd. From the USCCB site:
The Roman Church has been singing the “O” Antiphons since at least the eighth century….They are a magnificent theology that uses ancient biblical imagery drawn from the messianic hopes of the Old Testament to proclaim the coming Christ as the fulfillment not only of Old Testament hopes, but present ones as well. Their repeated use of the imperative “Come!” embodies the longing of all for the Divine Messiah.
Regarding today’s “O” Antiphon, given in its entirety at top, yes, we need rescue these days (all days, to be sure, but now at least as much as ever). In a world that largely wishes to push God out, or at least keep Him in His place (behind closed doors in your home or place of worship), wouldn’t it be awesome if our Leader would come in Power sooner rather than later (see Lk 22:69 and Lk 21:25-28)?
Meanwhile, it is up to us, who claim to be faithful, to take seriously Jesus’ instruction in the Our Father to hasten the coming of His Kingdom by praying and working “that all people submit to God’s reign” (per OT prophecies from which the “O” Antiphons themselves were developed) and “that God reign in [my] own life” for starters. (Mitch and Sri in The Gospel of Matthew, p. 106).